Improved machine for threading screw-caps



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UNITED STATES PATENT OFFICEo JOHN L. MASON, OE NEW vonk, N. Y.

IMPROVED MACHINE FOR THREADING SCREW-CAPS.

Specification forming part of Letters Patent No. 76,220, dated March 31, 1868.

To all whom it 'may concern:

Be it known that I, JOHN L. MASON, of the city of New York, county and State of New York, have invented a new and Improved Machine for Threading ,Screw-Caps and I do hereby declare the following to be a full, clear, and exact description, which will enable those skilled in the art to make and use the same, reference being had to theaccompan ying drawings, formingpart of this specification, in which drawings- Figure l represents a longitudinal vertical section of this invention. Fig. 2 is a plan or top view of thesame. Fig. 3 is a transverse section of the same, the line x Fig. 2, indicating the plane of section and looking in the direction ofthe arrow opposite to that line.

Similar letters indicate similar parts.

This invention consists in the arrangement of affseries of roller-dies secured in a disk or face-plate at equal distances from its center, in combination with a screw-chuck, which is secured to the end of a mandrel, -either the disk which carries the roller-dies onthe mandrel with the screw-chuck being so constructed that a revolving and an advancing or receding motion can be imparted to the same in such a manner that when a sheet-metal cap is placed on the screw-chuck and the roller-dies are brought to act thereon a screw-thread is pressed into said sheet-metal cap and the operation of manufacturing screw-caps is rendered safe and easy.

A represents a head-block, which forms the bearings for a spindle, B, to the end of which is rigidly attached the disk or face-plate C. The spindle B may be stationary, as shown in the drawings, or it may be movable, as will be` hereinafter explained.

The face-plate C is provided with three or more radial slots, ct, to receive the studs b, which form the bearings for the roller-dies c.

These dies revolve freely on their studs, and

the studs are provided with screw-threads and secured in their slots by jam-nuts, or in any other suitable manner so that they can be adjusted, and that the roller-dies can be brought to the required distance from the surface of theface-plate.

Each of the roller-dies is provided with one or more projecting circular beads or ridges, and if a die has two or more such ridges it is also provided with a shoulder, d. The distance.

of the ridges ofthe die corresponds to the pitch of the screw-thread to be produced in the sheetmetal cap, and said ridges rise beyond the shoulder d to a distance corresponding to the depth of the thread to be produced, so that when the die acts on the sheet-metal cap its ridges depress the sheet metal into the screwthreads of the chuck, and the shoulder d prevent-s the sheet metal from rising or buckling up in front of the ridges.

D is the screw-chuck, which is rigidly attached to the end of the mandrel E. This mandrel is provided with a screw-thread, c, the pitch of which corresponds with that of the thread of the screw-chuck, and which screws in a nut, f, which is firmly secured in the headblock F. By imparting to the mandrel a revolving motion, therefore, the screw-chuck is caused to revolve and to advance toward or recede from the face-plate C for the distance of one thread for each revolution.

The motion of the mandrel is produced by suitable gear-wheels, which must be so arranged that said mandrel advances Jthe required distance and then returns automatically. Any mechanism--such, for instance, as is commonly used on metal-planers-will produce this effect, and any further explanation thereof is deemed superliuous here.

If desired, the mandrel E, with the screwchuck, can be kept stationary, and the faccplate G, with the roller-dies, must then be so arranged that it can be revolved and made to advance toward or recede from the screwchuck. y

The sheet-metal cap which is to be provided with a screw-thread is spun or stamped to fit the screw-chuck, and as this chuck is made to revolve and to advance toward the face-plate G the roller-dies act on the sheet metal and depress it into the threads of the chuck..

By havingroller-dies with two or more ridges the sheet-metal cap is eft'ectually prevented from shift-ing on the chuck, and the shoulder d prevents the sheet metal from buckling up in front of the dies.

For sheet-metal caps of different sizes different screw-chucks and mandrels must be provided, and in order to be able to change these mandrels readily I have arranged the nut f of the mandrel E so that it can be easily re- 2 vegaa moved and replaced by another, which is eapable of receiving a mandrel with the desired screw-chuck.

If desired, the roller-dies can be replaced by simple round-pointed chasers, which are screwed t0 the face-plate and aet on the screwcap in a similar manner to the'roller-dies.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

The arrangement of one or more roller-dies, o, secured and made adjustable i'n a disk or face-plate, G, in combination with the screwehuck D and longitudinally-sliding mandrel E, substantially as and for the purpose shown and described.

JOHN L. MASON. Witnesses:

W. HAUFF, E. F. KASTENHUBER. 

